Are they really deaf, dumb and blind??

Quran says in several places that the disbelievers are deaf, dumb and blind. For example it is mentioned in the Quran,
"The example of those who disbelieve is like that of one who shouts at what hears nothing but calls and cries cattle or sheep - deaf, dumb and blind, so they do not understand."
(The Noble Quran, 2:171)
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But why it says like this way?
Ibn Kathir in his tafsir says,
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"(And the example of those who disbelieve...),
meaning, in their injustice, misguidance and ignorance, they are just like wandering animals, not understanding what they are told; if the shepherd heralds them or calls them to what benefits them, they would not understand what is actually being said to them, for they only hear unintelligible sounds."
(Tafsir from Ibn Kathir)
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But there remains a doubt.
Why Quran is criticising the disbeliever like a way of insult?
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Previously I couldn't understand this point and saw some non-muslim's objection on this matter. But later, from my own experience of life, I realised it like this way as if I am seeing the tafsir infront of me.
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The fact is that the objective of Quranic point of view is neither to insult nor to satisfy someone. Rather, the verses of the Quran tell about the truth. One may like it, or may dislike it too. But that will not change the truth.
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The people who hate Islam, if you say to them something or explain them something, they will behave like deaf, dumb and blind most of the time.
Ibn Kathir says,
"They are deaf, dumb, and blind.
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means, they are deaf, as they do not hear the truth; mute, as they do not utter it; and blind, as they do not see or recognize its path and way."
(Tafsir from Ibn Kathir)
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But it is not like that they do not have the power of understanding. Rather they do not want to understand. Their mentality has been set in the system of rejection of faith. So you can consider it as a "Kufr System", that means they have set their mind in such way that they will not care of what you say!
If you explain them everything, prove them something as correct one or show them signs, yet they will not ponder on it. They just want to find fault and objection and pose their negative questions one after another.
If you think deeply on it, then get the point; how can they pose such intelligent negative questions if they do not have the power of thinking and understanding???
Think about it.
The point is that they have sufficient power of understanding. But they want to use it in a wrong way. And the way has been set in the world of their mind in such manner that your words of truth can not touch their heart because of their "Kufr System" in mind. And such system works like this way that if something (whether it is Islam or any other issue) goes against their wish and desire, they just can't digest it and show their arrogance and double standard.
But do not think that they are trying to prove that Quranic point of view is incorrect. Rather, they are trying to flee away from the truth giving mere objection running after their own desire.
That's why Allah says,
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"Have you seen the one who takes as his god his own desire? Then would you be responsible for him?
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Or do you think that most of them hear or reason? They are not except like livestock. Rather, they are [even] more astray in [their] way."
(The Noble Quran, 25:43-44)